| 摘要 |
PURPOSE:To enhance the hFE and to obtain a semiconductor device having low noise by a method wherein breadth of a base is formed narrowly on the emitter layer side, and leading out of the base electrode is performed from an ion implanted shallow layer. CONSTITUTION:An SiO2 mask 5 is provided on an N type Si layer to perform diffusion boubly to form the P type base 2, the N<+> type emitter 3. Openings are formed selectively in the SiO2 mask 5, B ions are implanted to provide the shallow P<+> type layer 4 making a part thereof to be doubled with the base 2, and annealing is performed to activate inactive impurity and to crystallize Si. An opening is formed in the generated SiO2 layer 8, and the base electrode 7 is adhered thereon. By this constitution, because carriers 9 to be implanted into the side from the emitter 3 are reduced as compared with customary structure (dotted line), and the area of the sideward base part is reduced to reduce infuence of contamination, recombination quantity of the carriers 9 is reduced remarkably. Accordingly reactive current is reduced to increase carriers reaching the collector and to increase the hFE, and the element having low noise can be obtained. Moreover because the layer 4 is shallow and broad, reaching of carriers is small, and satisfactory connection of base can be formed. |
